This invention relates generally to a system for individually energizing each of a plurality of output devices including fault detection apparatus, and more particularly to an approach lighting system for an airport runway having means for detecting the number of faults of runway alignment indicator lights.
A prior system for actuating sequenced flashing lights in an approach lighting system utilizes a motor in conjunction with cam-actuated microswitches for sending control signals to the approach runway lights. A different type of system utilizes a stepping motor for sequentially sending control signals to the lights.
Often, a malfunction may occur in one or more of the lights, thereby reducing the effectiveness of the lighting system.
Previous attempts at detecting the number of faults of lights used in a runway approach lighting system include apparatus for sensing the transmission of a trigger signal for operating each light. However, even when a trigger signal is transmitted to a light, the light may fail to operate, a malfunction which may not be sensed by analyzing the outgoing trigger signal.
Other types of monitoring systems require the intensity of the flashing lights to be increased greatly, thereby necessitating the use of a separate test routine which, in turn, results in undesirable downtime of the system.